Submission #1093088

#	Time	Username	Problem	Language	Result	Execution time	Memory
1093088		vladilius	Meetings 2 (JOI21_meetings2)	C++17	100 / 100	530 ms	40272 KiB

meetings2

#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using pii = pair<int, int>;
#define pb push_back
#define ff first
#define ss second
 
int main(){
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    
    int n; cin>>n;
    vector<int> g[n + 1];
    for (int i = 1; i < n; i++){
        int x, y; cin>>x>>y;
        g[x].pb(y);
        g[y].pb(x);
    }
    
    vector<bool> used(n + 1);
    vector<int> sz(n + 1), d(n + 1);
    function<void(int, int)> fill_sz = [&](int v, int pr){
        sz[v] = 1;
        for (int i: g[v]){
            if (i == pr || used[i]) continue;
            d[i] = d[v] + 1;
            fill_sz(i, v);
            sz[v] += sz[i];
        }
    };
    
    function<int(int, int, int&)> find = [&](int v, int pr, int& S){
        for (int i: g[v]){
            if (i == pr || used[i]) continue;
            if (2 * sz[i] >= S){
                return find(i, v, S);
            }
        }
        return v;
    };
    
    vector<pii> all;
    function<void(int, int, int&)> add = [&](int v, int pr, int& u){
        all.pb({v, u});
        for (int i: g[v]){
            if (i == pr || used[i]) continue;
            add(i, v, u);
        }
    };
    
    vector<int> out(n + 1, 1), p(n + 1);
    vector<pii> dd[n + 1];
    multiset<int> st;
    function<void(int)> arvid = [&](int v){
        fill_sz(v, 0);
        v = find(v, 0, sz[v]);
        used[v] = 1;
        
        d[v] = 0;
        fill_sz(v, 0);
        all.clear();
        for (int i: g[v]){
            if (used[i]) continue;
            add(i, 0, i);
            p[i] = 0;
        }
        
        int f = sz[v] / 2;
        for (int i = 1; i <= f; i++) dd[i].clear();
        for (auto [x, y]: all){
            dd[sz[x]].pb({x, y});
        }
        
        st.clear();
        for (int i = f; i > 0; i--){
            for (auto [x, y]: dd[i]){
                if (p[y] < d[x]){
                    if (!p[y]){
                        st.insert(d[x]);
                    }
                    else {
                        st.erase(st.find(p[y]));
                        st.insert(d[x]);
                    }
                    p[y] = d[x];
                }
            }
            if (st.size() < 2) continue;
            auto it = prev(st.end());
            int sum = *it + *prev(it) + 1;
            out[i] = max(out[i], sum);
        }
        
        for (auto [x, y]: all){
            int k = min(sz[x], sz[v] - sz[y]);
            out[k] = max(out[k], d[x] + 1);
        }
        
        for (int i: g[v]){
            if (used[i]) continue;
            arvid(i);
        }
    };
    arvid(1);
    
    for (int i = n - 1; i > 0; i--) out[i] = max(out[i], out[i + 1]);
    
    for (int i = 1; i <= n; i++){
        cout<<((i % 2) ? 1 : out[i / 2])<<"\n";
    }
}

• Subtask 1: 4 / 4
• Subtask 2: 16 / 16
• Subtask 3: 80 / 80